/*
 * This file contains code from "C++ Primer, Fourth Edition", by Stanley B.
 * Lippman, Jose Lajoie, and Barbara E. Moo, and is covered under the
 * copyright and warranty notices given in that book:
 *
 * "Copyright (c) 2005 by Objectwrite, Inc., Jose Lajoie, and Barbara E. Moo."
 *
 *
 * "The authors and publisher have taken care in the preparation of this book,
 * but make no expressed or implied warranty of any kind and assume no
 * responsibility for errors or omissions. No liability is assumed for
 * incidental or consequential damages in connection with or arising out of the
 * use of the information or programs contained herein."
 *
 * Permission is granted for this code to be used for educational purposes in
 * association with the book, given proper citation if and when posted or
 * reproduced.Any commercial use of this code requires the explicit written
 * permission of the publisher, Addison-Wesley Professional, a division of
 * Pearson Education, Inc. Send your request for permission, stating clearly
 * what code you would like to use, and in what specific way, to the following
 * address:
 *
 *  Pearson Education, Inc.
 *  Rights and Contracts Department
 *  75 Arlington Street, Suite 300
 *  Boston, MA 02216
 *  Fax: (617) 848-7047
*/

#include <iostream>
using std::ostream;
using std::cout;
using std::endl;
#include <string>

// class that has a pointer member that behaves like a plain pointer
class HasPtr
{
public:
	friend ostream& operator<<(ostream&, const HasPtr&);
	// copy of the values we're given
	HasPtr(int* p, int i): ptr(p), val(i) { }

	// const members to return the value of the indicated data member
	int* get_ptr() const
	{
		return ptr;
	}
	int get_int() const
	{
		return val;
	}

	// nonconst members to change the indicated data member
	void set_ptr(int* p)
	{
		ptr = p;
	}
	void set_int(int i)
	{
		val = i;
	}

	// return or change the value pointed to, so ok for const objects
	int get_ptr_val() const
	{
		return *ptr;
	}
	void set_ptr_val(int val) const
	{
		*ptr = val;
	}

private:
	int* ptr;
	int val;
};

void show_copy_control()
{
	int i = 42;
	HasPtr p1(&i, 42);
	HasPtr p2 = p1;
	cout << p2.get_ptr_val() << endl;

	p1.set_ptr_val(0);
	cout << p2.get_ptr_val() << endl;
}

int main()
{
	show_copy_control();

	int obj = 0;

	HasPtr ptr1(&obj, 42);  // int* member points to obj, val is 42
	HasPtr ptr2(ptr1);      // int* member points to obj, val is 42

	cout << "(1) ptr1: " << ptr1 << endl << "ptr2: " << ptr2 << endl;

	ptr1.set_ptr_val(42); // sets object to which both ptr1 and ptr2 point
	ptr2.get_ptr_val();   // returns 42
	cout << "(2) ptr1: " << ptr1 << endl << "ptr2: " << ptr2 << endl;

	ptr1.set_int(0);   // changes val member only in ptr1
	ptr2.get_int();    // returns 42
	ptr1.get_int();    // returns 0

	cout << "(3) ptr1: " << ptr1 << endl << "ptr2: " << ptr2 << endl;

	int* ip = new int(42); // dynamically allocated int initialized to 42
	HasPtr ptr(ip, 10);    // HasPtr points to same object as ip does
	delete ip;             // object pointed to by ip is freed
	ptr.set_ptr_val(0); // disaster: The object to which HasPtr points was freed!

	// this statement or the previous one are likely to crash --
	// the object to which ptr points was deleted
	cout << "(4) ptr: " << ptr << endl;

	return 0;
}

ostream& operator<<(ostream& os, const HasPtr& hp)
{
	cout << "*ptr: " << hp.get_ptr_val() << "\tval: " << hp.get_int() << endl;
	return os;
}

